### Mathematisch-Naturwissenschaftliche Fakultät

## Institut für Physik

### Fachgebiet: Theoretische Physik

Betreuer: Prof. Dr. Heinrich Stolz

**Dipl.-Phys.** **Patrick** **Ludwig**

(e-mail: patrick.ludwig@uni-rostock.de )

*Structure Formation in Strongly Correlated Few-Particle Systems in Traps*

The objective of the present work is the theoretical investigation
physical structure formation by means of
computational simulation methods. Of particular interest are charged
few-particle systems in external trapping potentials, which allow one
to realize
and control strong correlation and quantum effects. Such 'artificial
atoms' have unique features absent in real atoms: by controlling the
confinement strength they can be transformed from a weakly coupled
state to a strongly coupled, crystal-like phase.

The first central topic is devoted to the structural properties of
3D Coulomb crystals, which have been observed in trapped ion systems as
well as in (multi-component) complex plasmas. The ground state
properties, such as the shell structure, are studied by first-principle
molecular dynamics simulations.
The detailed comparison of the theoretical results with experiments
provides the basis for a theory of these strongly correlated classical
systems.

The second major topic concerns electron-hole quantum plasmas in
dimensionality reduced semiconductor heterostructures.
At first, the realization of a quantum Stark confinement for spatially
indirect excitons in a single quantum well is investigated in view of
an experimental implementation.
Furthermore, the effects of field-strength, temperature, density,
exciton dipole moment, and electron-hole mass asymmetry are extensively
studied by means of quantum Monte Carlo simulations. As a universal
melting criterion for classical and quantum few-particle systems a
modified version of the Lindemann parameter for the pair distance
fluctuations is introduced.